1. Field of the Invention.
The present invention relates to a method and apparatus for producing dual threads on an object, and more particularly relates to a method and apparatus for producing synchronized dual internal and external threads in/on the cylindrical portion of an object, wherein both sets of synchronized internal and external threads are adapted to engage corresponding synchronized external and internal mating threads on a mating object for effecting the threaded union therebetween.
2. Description of the Prior Art.
It is well known to have a pipe or other cylindrical object that incorporates dual threads, that is a set of male threads on the exterior thereof and a set of female threads on the interior thereof. Heretofore, however, the interior and exterior threads of such cylindrical objects have not borne any relationship to each other, and it has therefore not been necessary to either produce both sets of threads simultaneously or otherwise establish a relationship between the two sets of threads during manufacture. Therefore, traditional methods of cutting or forming exterior and interior threads on/in a cylindrical object have been adequate. In other words, the exterior and interior threads have been formed in conventional manners, as in/on a lathe, milling machine, screw machine, etc., without regard to any relationship between the two sets of threads.